Folding stairs



Oct. 23, 1951 E. E. PIERCE 2,572,281

FOLDING STAIRS Filed July l5, 1949 2 SHEETS- SHEET l ATTORNEY o1.23,1951 E. E. PIECE 2,572,281

FOLDING STAIRS Filed July l5, 1949 Ernest E.' P/erce' IN V EN TOR.

A TTORNE Y Patented Oct. 23, l1.951

`UNITED STATES PATENT OFFICE 2,572,281 FL-iiING STAIRS Ernest E. Pierce,Dallas; Tex. Appiicatitn July' 15, 1949, serai No. 164,840

5 Claims.

This invention relates to folding stairs and more particularly tosectional staircase especially useful in gaining access to buildingattics.

The principal object is to provide a sectional stairway having a primaryand a secondary spring counterbalance, the former acting through themedium of an eccentric pulley or cam to exert a force tending to movethe hinged sections of the stairway towards folded position to minimizethe extending and folding effort, while the secondary counterbalanceserves the dual purpose of resisting the effort to displace thesubsection with respect to the main section of the stair both in thefolding and extending operations, .Moreover, and cooperating withthesecondary counterbalance is a cable connected between the eccentricactuating arms of the main stair section and selected supporting arms ofthe subsection and is effective to exert a force tending to maintainaxial alignment of the pivoted sections of the eccentric actuating armwhen the stair sectionsare in extended position.

Other and lesser objects will become apparent as the descriptionvproceeds, taken in connection with the accompanying drawing, wherein:

Figure 1 is a perspective view of a folding stairway embodying theinvention, shown in extended position.

Figure 2 is a side elevational view thereof in folded position. l

Figure 3 is a side elevational view in partly extended position andshowing in dotted lines the full extended position thereof.

Figure 4 is a fragmentary side elevational view showing one of theeccentrics in detail.

Figure 5 is a sectional view taken on line 5 5 of Figure 4, and

Figure 6 is a sectional view taken on line t-G of- Figure 3.

Continuing with a more detailed description of the drawing, referencenumeral I denotes frag'- mentarily a oor and ceiling construction inwhich is made an opening to accommodate the stair, the opening beingdened by a suitable frame II.

The stairway is made up of two or more sections, depending upon theheight of the ceiling from the floor and the section which is joined tothe. frame I I is referred to herein as the main stair section I2 andconsists of the side members The between which are spaced the treads I3.main section I2 is pivotally. connected tothe frame II by meansofcurvedstraps III, one being affixed to each of. the side members ofthe section` and, extendinghrough slots` I V(Figs. 3 and' 6) 4.in

an end of the frame and engaging pins journaled in bearings I6, mountedon the outer surface of the end members of the frame. Affixed to theunderside of the main section I2 is a cover I'I which is adapted toclose the opening in the ceiling when the stair sections are raised tofolded position.

The ends of the side members of the main stair section I2, opposite thehinge, are each obliquely" formed to conform to the similarly formedendsof the side members of a sub-section I8, and which are joined to theend of the main sectionthrough the medium of a pair of arms I 9 on eachside of the stair. Each pair of arms are pivoted to plates 20` affixedto the side members of each stair section and which are each providedwith longitudinally aligned holes for adjustably receiving the pivotbolts of the arms I9. The particular manner of attaching the arms I9V tothey respective stair sections insures parallelism of the' to the top ofa side member of the frame I I. Ani identical arrangement is provided onthe opposite' side of the frame. The cam wheels or eccentrics 2I operatein recesses 24 made therefor in theouter surfaces of the frame sidemembers and on` the inner end of each shaft 22 is aflixed the upper endof the upper section 25 of an arm which will be referred to herein asthe eccentric actuating arm. The section 25 of the arm is pivoted at 25to2 a lower section 27 and the lower end of this sec-l tion, in turn, ispivoted adjustably to a plate- 28, aiiixed to the outside of one of theside members of the main stair section I2, adjacent the endl oppositeits hinge.

Anchored to brackets 29 at the hinged end of` the stair are the ends ofmain counterbalance springs 30 which extend along the tops of. theframeside members and to the opposite end of each of these springs is affixedthe end of acable 3 I. The opposite end of the cable is secured at 32?(Fig. 4), a selected point in the periphery of the eccentric wheel 2I,so that the cable will' follow in the groove of the wheel as the latterrevolves'y during raising and lowering movements f the" main stairsection.

It is apparent from the foregoing that as thef main section I2 islowered, the sections v25V and 21! of the eccentric actuating arm willmove towards axially.. aligned position and in so moving, the

wheel 3I will rotate in a clockwise direction to wind the cable 3lthereon, thus storing energy in the springs 30 eiective to nearlybalance the weight of the stair sections I2 and I8. A crossmember 33underlying the strap hinges I4 of the main section I2 constitutes a stopand is positioned to determine the angle of the section l2 in loweredposition.

On each side of the stair sections there is Drovided a coil spring 34 ofless strength than the spring 30 and is connected at one end to a plate35, affixed to a side section of the main stair section and at itsopposite end at 35 to the lowest of the two parallel arms I9 whichconstitute the support for the sub-section I8. The springs 34 areconnected to the arms I9 at an appropriate point to exert a forcetending to resist downward displacement of the sub-section I8andconstitutes the secondary counterbalance herein referred to. Thepresence of these springs in the assembly minimizes the eiiort requiredto move the subsection into and out of folded relationship with itscompanion section.

When the stair is in folded position, as exemplified in Figure 2, themain section i2 is moved to the position shown in dotted lines in thisgure by pulling downwardly on the short length of cord 31, dependingfrom an end thereof. This is the initial step in the operation ofunfolding the sections. When lowered, the main section brings with itthe sub-section I8 but the latter is held against downward displacementby the action of springs 34 until the lower end of the sub-section isgrasped and pulled to a position where its weight will overcome theresistance of the springs 34, whereupon it will swing under control ofthese springs into axial alignment with the main section I2, as inFigure l.

As the sections assume axial alignment as explained above, a cable 38,connected to and extending between the eccentric actuating arm and oneof the sub-section supporting arms I9, is brought under tension andimposes a force on the upper sections 25 of the eccentric actuating arm,tending to bring it into longitudinal alignment with the companionsection 28 thereof, thus to overcome any tendency of the springs 3 toraise the foot of the stairs oi the door. In other'words, the cables 38,being joined to the eccentric actuating arms at one end and at theirother ends to arms I9. after passing over pulleys 39, afiixed to theside members of the main section I2, are effective to maintain deadcenter relationship oi the pivoted sections of the eccentric actuatingarms and thus lend stiffness thereto as long as the stair sections arein extended position but the force so exerted by the cables 38 is notsuch that it cannot be overcome simply by lifting upward on thesub-section I3 and thus releasing both stair sections to the force ofthe primary and secondary counterbalancing springs 30 and 34respectively which, while minimizing the load, are not wholly adequateto restore the stair sections to folded -V position in the ceilingopening.

Each of the side members of the main stair ,section I2 has a hand rail40 mounted thereon. iIt will also be observed, especially in Figure l,that the ends of the side members of the subsection I8 each carries aguide plate 4I which is brought to bear against the side members of themain section I2 when the ends of the side members of the sections arebrought into juxtaposition yin extended position of the stair and serveas stabilizers, holding the sections in alignment.

Manifestly, the construction as shown and de- 4 scribed is capable ofsome modification and such modication as may be construed to fall withinthe scope and meaning of the appended claims is also considered to bewithin the spirit and intent of the invention.

What is claimed is:

1. A folding stairway comprising a horizontal frame, a main stairsection pivoted at one' end te an end of said frame and adapted to bedisposed inoperatively within the confines of said frame, a sub-stairsection, a pair of parallel arms on each side of said stair sections forpivotally supporting said sub-stair section on said main stair section,a toggle on each side of said frame, each comprising a link pivoted atone end to one side of said main stair section, and an arm pivoted atone end to the opposite end of said link, an eccentric pulley mounted oneach side of said frame, to the shaft of which the opposite end of saidlatter arm is aiiixed to move therewith, a primary counterbalancingspring on each side of said frame, said springs having their endsattached to the peripheries or said pulleys and their opposite ends toan end of said frame to exert a lifting force on said stair sectionsthrough said eccentric pulleys and said toggle, a pair of secondarycounterbalancing springs having their upper ends connected to the sidesof said main stair sections and their lower ends to one of said parallelarms and effective to exert a lifting force on said sub-stair sectionand flexible means for stabilizing said toggle in extended position ofsaid stair sections.

2. A folding stairway including a horizontal frame, a main stair sectionpivoted at one end to an end of said frame for movement into eX- tendedand inoperative positions, a sub-stair section supported by and movableinto extended and inoperative position on said main stair section, aneccentrically mounted wheel on each side of said frame, a pair ofprimary counterbalancing springs connected to the frame at one end, a,Wire line connected at one end to each of said counterbalancing springs,said wire lines being connected to and partially wound on theperipheries of said wheels, a toggle on each side of said stairwaycomprising a link pivoted at one end to the main stair section and anarm pivoted at one end to the opposite end of said link and ainxed atits other end to an axle of one of said eccentric wheels to rotate thelatter as said stair sections are actuated under the influence of saidspring counterbalance tending to urge said stair sections towardinoperative confinement in said frame, a pair of secondarycounterbalance springs tending to urge the sub-stair section towardsfolded relationship on said main stair section and exible means adaptedto urge the arm and link of said toggle into longitudinal alignment assaid stair sections are moved to extended position to stabilize saidstair sections in said extended position.

3. A folding stairway including a frame, a main stair section and asub-stair section, the latter being superimposed on the main vstairsection in inoperative position and disposed in axial alignment thereofin lextended position of said sections, an eccentrically mounted wheelon each side of vsaid frame, a toggle on each side of said stairway,said toggles each consisting of a link having its lower end pivoted tothe lower end of said main stair section and an arm pivoted at one endto said link, the upper end of said arm being aflixed to the axles ofsaid wheels to actuate the same when said stair sections are moved, apair ofprimary counterbalance springs, an end of each being anchored toan end of said frame, each having a wire line connected thereto, theopposite ends of said wire lines being connected to and partially woundon said wheels to resist rotation thereof during lowering movement ofsaid stair sections, a pair of parallel arms pivotally connecting saidmain and sub-stair sections, spring means connecting said main andsub-stair sections for resisting movement of said sub-stair sectiontowards extended position and means for connecting each arm of said pairof parallel arms with an arm of each of said toggles for stabilizingsaid stair sections in extended position.

4. A folding stairway including a horizontal frame, a main stair sectionpivoted at one end to an end of said frame, a hand rail mounted on andspaced from each side of said main stair section, a sub-stair section, apair of parallel arms pivoted at their ends to said main and sub-stairsections to support said sub-stair section for swinging displacementinto extended relationship with said main frame section and to disposesaid sub-stair section above said hand rails in folded position of saidstair sections, a counterbalance spring on each side of and connectingsaid stair sections to resist movement of the sub-stair section towardsextended position, a toggle on each side of said main stair sectioncomprising a link having its lower end pivoted to said main stairsection and an arm pivoted to the upper end of said link, an eccentricwheel on each side of said frame, means lxedly connecting the upper endof the arms of said toggle to the axles of said eccentric wheels, asecond counterbalance spring on each side of said frame, one end beinganchored to an end of said frame, wire lines affixed at their ends tothe ends of said springs and having their opposite ends aiiixed to saideccentric wheels to resist rotation thereof as imposed by said sectionalarms during movement of said stair sections towards extended positionand means connecting an arm of each pair of said parallel arms to thearm of each of said toggles for stabilizing said stair sections inextended position.

5. A folding stairway comprising a horizontal frame, a pair ofrelatively pivoted stair sections, one of which is pivoted at one end toan end of said frame, hand rails on said latter stair section, a pair ofparallel arms on each side of said main stair section supporting thecompanion stair section for movement to a position above said hand railsand to an extended position in relation to the first of said stairsections, spring means resisting displacement of the companion stairsection to extended position, a wheel mounted eccentrically on an axleat each side of said frame, a toggle on each side of said stairsections, the lower ends of said toggles being pivoted to the rst ofsaid stair sections and afxed at their opposite ends to said wheelaxles, springs aiixed at their ends to an end of said frame, wire linesaixed at their ends to the ends of said springs and at their oppositeends to the peripheries of said wheels to resist rotation thereof duringmovement of said stair sections to extended position and meansconnecting one of each pair of said parallel arms with each said togglesfor stabilizing said stair sections in extended position.

ERNEST E. PIERCE.

REFERENCES CITED UNITED STATES PATENTS Name Date Marschke Mar. 16, 1943Number

